Amplifying system



M y 17, 1932- w. F. EAMES 1,858,267

AMPLIFYING SYSTEM Filed Aug. 23, 1930 lNVENTOR MY/famFE'ames.

flaw/W ATTORNEY Patented May .1-7, 1932 UNITED STATES PATENT OFFICE WILLIAM F. EAMES, OF EDGEWOOD, IIENIN'SYL VANIA, ASSIGNOB TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA AKPLIFYING SYSTEM Application filed August as, mo. Serial No. 477,827.

My invention relates to the amplification of voltages or currents and has particular relation to the amplification of voltages or currents of the magnitudes and characteristics ordinarily occurring in motor-control systems, switch gear, power machinery and similar electrical apparatus.

It is an object of my invention to provide an arrangement by means of which variations of current or voltage in one circuit may be faithfully reproduced as variations of current or voltage of a different magnitude in another circuit so that translating devices, such as relays, regulators or similar devices, may be controlled in accordance with the current or volta e produced in the latter circuit.

Another 0%ject of my invention is to provide an arrangement by means of which,an input voltage and an output voltage are translated into the form of opposing magnetomotive forces and-the output voltage varied in response to the unbalanced resultant of these magnetomotive forces, in a manner to maintain the balance, so that the output voltage is,

at all times, proportional to the input voltage.

Other objects of my invention will become evident from the following detailed descrip tion, taken in conjunction with the accompanying drawin s in which:

Figure 1 is a iagrammatic view of a system embodying my invention.

Fig. 2 is a diagrammatic view of a portion of the system shown in Fig. 1.

Referring to the drawings, the apparatus shown in Fig. 1 comprises a vibrating relay R having a magnetic structure 1 and a movable armature 2. The relay R may be of any suitable type but is, preferably, of the movingcoil type disclosed in a copending application of Walter E. Schaelchlin, Serial No. 221,422, filed Sept. 23,1927 and assigned to the Westinghouse Electric and Manufacturing Company.

The magnetic structure 1 of the relay R comprises an outer shell portion 3 and an inner core portion 4. The movable armature 2 is of non-magnetic material and is pivoted,-at 5, to a suitable support (not shown). A cylin- 60 der 6 of non-magnetic material is mounted on ture. The space between the stationary contact members 8 and9 is sufii'cient for the movable contact member 7 to assume a neutral position in which neither stationary contact member is engaged.

The armature 2 is biased by any suitable means, which I have illustrated as a spring 10, to a position in which the movable contact member 7 engages the stationary contact member 8. An adjustable support 11 is provided for adjusting the tension of spring 10.

A demagnetizing winding 12, a biasing winding 13 and an input winding 14 are mounted on the core portion 4 of the magnetic structure, and a coil 15 is mounted on the cylinder 6 in inductive relation to the windings 12, 13 and 14, through the magnetic structure 1. 1

A pair of supply conductors L1 and L2 are arranged to be connected to a suitable direct current source S by means of a switch 16. A pair of resistors r-l and 1'2 of substantially equal resistance are connected in series between the supply conductors L1 and L2. The stationary'cont'act members 8 and 9 are connected to supply conductors L2 and L1, respectively.

The demagnetizing winding 12 of relay R is connected, by means of a conductor 17, to the mid-point of the circuit of resistors r1 and r2, and to the movable contact memher 7 in series with a potentiometer r3. A pair of output conductors 18 and 19 are connected to the conductor 17 and to the adjustable tap of otentiometer 1'-3, respectively.

The movable coil 15 and the bias winding 13 of the relay R are connected to supply conductors L1 and L2 in series with an adjustable resistor r4=, in such relation that the fluxes set up in these windings, upon closure of the switch 16, tend to rotate the armature 2 counter-clockwise against its bias.

The winding 14.- is connected to a pair of 100 input conductors 20 and 21 in such relation to the winding 12 that the magnetomotive force set up by the input winding 14, when the system is in operation, is opposed by the magnetomotive force set up by demagnetizing winding '12.

Fig. 2 shows, in simplified form, the connections of the output conductors 18 and 19 with the potentiometer 1'3, the demagnet izing winding 12,.resistors 1'1 and 1'2, contact members 7,8 and 9 and supply conductors L1 and L2.

The operation of the above. described apparatus may be set forth as follows: the switch 16 is first closed to connect the supply conductors L1 and L2 to the direct-current source S. The resistor r-4 is now adjusted until the force on the armature 2, caused by the reaction of the current in coil 15 upon the magnetic field set up by winding 14, balances the tension of spring 10, and the movable contact member 7 stands in neutral position. If the input conductors 20 and 21 are now connected to the source of voltage which is to be amplified, a current flows in the input winding 14 which sets up a magnetomotive force in the magnetic structure 1, causing a change of flux and a consequent change in the force acting upon the armature 2. The movable contact member 7 now moves into engagement with the one or the other of stationary contact members 8 and 9, depending upon the direction of current in the winding 14.

Assuming that the current in the winding 14 is in such direction as to cause movable contact member 7 to engage stationary contact member 8, a circuit is completed from the mid-point of the circuit of resistors r-1 and r2, through conductor 17, demagnetizing winding 12, potentiometer 1'3 and contactmembers 7 and 8, to supply conductor L2.

A current commences to build up in the demagnetizing winding 12 and that winding exerts a magnetomotive force in opposition to the magnetomotive force set up by winding 14.. When the magnetomotive force produced by winding 12 becomes equal to that produced by winding 14, the movable contact-member 7 is disengaged from the stationary contact member 8. The circuit of winding 12 is now broken, and the winding 14 acts unopposed to again cause movable contact member 7 to engage stationary contact member 8.

The movable contact member 7 vibrates continuously in the manner described; the duration of its engagement with contact member 8 establishing an average current in the winding 12 of such value that the average magnetomotive force produced by winding 12 equals the magnetomotive force produced by winding 14.

If the value of current in winding 14 now maintained between the value of current in Y winding 14 and the value of current in winding 12, regardless of the value or direction of the former. The current in winding 12 be- Ing maintained roportional to the current in winding 14, the R drop across any portion of the circuit in which the winding 12 is included is also, neglecting inductive effects, proportional to the current in winding 14. As the output conductors '18 and 19 are connected across a portion of this circuit, the voltage existing between them is always proportional to the current in winding 14. v

The vibrations of a relay of the type described above are very rapid, the pulsations of output voltage being similarly rapid. Because of the comparatively high frequency of these pulsations, the inductance of a translating device, such as a relay connected to the output conductors 18 and 19, acts as a filtering device toreduce these pulsations. It is unnecessary, in most cases, therefore, to use external filtering devices in the output circuit.

While, because of the advantages of the arrangement, I prefer to use a relay, 'such as that shown, it will be understood that my invention may be practiced with other translating devices by means of which a voltage or current may be varied in response to the joint action of current in a pair of windings.

I do not wish to be restricted to the specific structural details, arrangement of parts or circuit connections herein set forth, as various modifications thereof may be efi'ected without departing from the. spirit and scope of my invention. I-desire, therefore,'that only such limitations shall be imposed as are indicated in the appended claims.

I claim as m invention:

1. The met 0d of amplifying voltages which comprises opposing a magnetomotive force proportional to an input voltage against a magnetomotive force proportional to an output voltage, and varying the output voltage in accordance with the unbalanced difference of said magnetomotive forces in a manner to reduce said difference.

'2. In a system for the amplification of voltages, a magnetic structure, an input winding interlinked with said magnetic responsive to the flux in said magnetic structure for maintaining a current in said demagnetizing winding of such value and direction that the magnetomotive force produced by said demagnetizin winding neutralizes the magnetomotive Iorce produced by said input winding, and means interconnecting said output conductors and said demagnetizing winding for maintaining a voltage between said output conductors proportional to the current in said demagnetizing winding.

3. In a system for the amplification of voltage, a magnetic structure, an input winding interlinked with said magnetic structure, a demagnetizing winding interlinked with said magnetic structure, a source, means responsive to the flux in said magnetic structure for intermittently establishing connection between said demagnetizing winding and said source of such direction and duration that the average magnetomotive force produced by said demagnetizing winding neutralizes the magnetomotive force produced by said input winding, output conductors, and means interconnecting said output conductors and said demagnetizing winding for maintaining a voltage between said output conductors proportional to the current in said demagnetizing winding.

4. In a system for the amplification of yoltages, a relay comprising an input wind- 7 ing, a demagnetizing winding and contact members operable in response to the resultant magnetomotive force produced by said windings, a source, conductors interconnecting said demagnetizing winding, said source and said contact members in such manner that a voltage from said source is impressed on said demagnetizing winding when said resultant magnetomotive force is greater than zero, in a direction to reduce said resultant, and output conductors connected with said demagnetizing winding in such manner that the voltage between said output conductors is maintained at a Value proportional to the current in said demagnetizing winding.

5. In a system for the amplification of voltage, a vi rating relay comprising a magnetic structure, an input winding and a de magnetizing winding mounted on said magnetic structure, an armature, a coil mounted on said armature in inductive relation to said windingsthrough said magnetic structure, and contact members controlled by said armature, a source, conductors completing a circuit including said source and said coil, conductors interconnecting said demagnetizing winding, said source and said contact members in such manner that a voltage from said source is impressed on said demagnetizing winding when the resultant of magnetomotive forces produced by said windings is greater than zero, in a direction to reduce said resultant, and output conductors conoutput conductors,

nected with said demagnetizin winding in such manner that the voltage etween said output conductors is maintained at a value proportional to the current in said demagnetizing winding.

6. In a system for the amplification of voltages, a vibrating relay comprising an input winding, a demagnetizing winding, a pair of stationary contact members, a movable contact member operable in response to the resultant magnetomotive force produced by said windings to engage either of said stationary contact members depending upon the direction of said resultant, a source, resistor means connected across said source, a conductor connecting said movable contact member to a mid-point of said resistor means in series with said demagnetizing winding, and conductors connecting each of said stationary contact members to a terminal of said source.

7. In a system for the amplification of voltage, a vibrating relay comprising a magnetic structure, an input winding and a demagnetizing winding mounted on said magnetic structure, an armature, a coil mounted on said armature in inductive relation to said windings through said magnetic structure, a pair of stationary contact members, a movable contact member mounted upon said armature in a position to engage either of said stationary contact members depending upon the position of said armature, a source, resistor means connected across said source, a conductor connecting said movable contact member to a mid-point of said resistor means in series with said demagnetizing winding, conductors connecting each of said stationary contact members to a terminal of said source and output conductors connected with said demagnetizing Winding.

In testimony whereof, I have hereunto subscribed my name this 22nd day of August,

WILLIAM F. EAMES. 

